Year1
- 型号：
- HH11-20/3
- 电流：
- 20A
- 种类：
- 熔断器式负荷开关
Low voltage enclosed load iron case switch-/3 is also called switch fuse group. It is suitable for switching on-load circuit manually and infrequently in AC power frequency circuits. It can also be used for line overload and short-circuit protection. The on-off circuit is completed by the contact knife, and the overload and short-circuit protection is completed by the fuse.
Low-voltage enclosed iron-loaded iron case switch-/3 is a switch with special arc-extinguishing contacts, arc-extinguishing device and spring circuit breaker. From a structural point of view, the load iron case switch is similar to the isolating switch (it has a visible disconnection point in the off state), but it can be used to open and close circuits, which is similar to a circuit breaker.
However, the circuit breaker can control any circuit, while the low-voltage enclosed load iron case switch-/3 can only switch the load current, or break the overload current, so it is only used to cut off and connect the circuit under normal circumstances. , and cannot be used to interrupt short-circuit fault current. However, its structure is required to be able to pass the fault current during the short circuit time without being damaged. Since the arc extinguishing device and contacts of the low-voltage enclosed iron-type load switch-/3 are designed to cut off and connect the load current, the iron-load switch should be used in conjunction with a high-voltage fuse in most cases, and the latter To take on the task of cutting off short circuit fault current. The opening and closing frequency and operating life of low-voltage enclosed iron-loaded switch-/3 are often higher than those of circuit breakers.
The advantage of the low-voltage enclosed load iron case switch-/3 is that it is relatively low-priced and is mostly used in distribution lines below kilovolts. Its arc extinguishing methods include air, compressed air, and vacuum arc extinguishing. With the continuous development of science and technology, the types and quality of load iron case switches have increased and improved.
The low-voltage enclosed load iron case switch-/3 has a simple arc extinguishing device with limited arc extinguishing ability. When the circuit is working normally, it is used to connect or cut off the load current, but it cannot be used when the circuit is open. To cut off the huge short-circuit current, the low-voltage enclosed iron-shell load switch-/3 has a visible disconnect point after disconnection, which is its characteristic.
The plastic-covered knife switches and iron-cased switches used before the 1980s are both low-voltage load switches. For low-voltage load switches with small capacity of high-voltage fuses, the opening and closing speed of the contacts is related to the operating speed of the handle. The operating mechanism of the low-voltage load switch with a large capacity adopts the spring energy storage action principle. The opening and closing speed has nothing to do with the speed of the handle operation. The structure is relatively simple and is equipped with a reliable mechanical interlocking device. The switch cannot be closed or switched after the cover is opened. The cover cannot be opened after closing, ensuring work safety.
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